[TASK] Cleanup Ajax URL inline settings

This change streamlines the use of Ajax URLs
by auto-publishing all Ajax URLs to JavaScript
inline settings.

All Ajax URLs can now also be looked up in
JavaScript by providing the AjaxID like that:

var ajaxUrl = TYPO3.settings.ajaxUrls['TxMyExt::process'];

All code has been adapted to reflect this change.

Resolves: #57096
Documentation: #56347
Releases: 6.2
Change-Id: I4a441f51dcb3551874082077c52918b3fc6a9b0f
Reviewed-on: https://review.typo3.org/28602
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind